Field of the Invention
The present invention relates to a light source optical system, a light source apparatus using the same, and an image display apparatus such as a projector, and in particular, relates to a light source apparatus using a laser diode (LD) light source and a projection display apparatus on which the light source apparatus using the LD light source is mounted.
Description of the Related Art
In recent years, a projector has been developed that can display a color image using a fluorescent body for converting blue light received from a LD light source into green light and red light.
Examples of such projector are discussed in US2010/0328632 and US2011/0292349.
US2010/0328632 discusses a technique for displaying a color image using blue light from a LD light source in addition to green light and red light emitted as fluorescent light. A fluorescent wheel is rotated and includes a diffusion layer that can transmit the blue light from the LD light source, and a fluorescent layer that acts as a fluorescent body (phosphor). If the diffusion layer has been irradiated with the blue light from the LD light source, the blue light passes through the fluorescent layer and is guided to an illumination optical system by a reflecting mirror. If, on the other hand, the fluorescent layer has been irradiated with the blue light from the LD light source, the green light and the red light are emitted in the direction of the light source and guided to the illumination optical system by a dichroic mirror.
US2011/0292349 discusses a technique for using blue light emitted from a blue light-emitting diode (LED) provided separately from an LD light source, in addition to green light and red light emitted as fluorescent light, thereby displaying a color image.